The Porsche 911's continuous product evolution over 50 years has become something of an often-repeated Top Gear gag, where both James May and Richard Hammond (despite being owners of the model) fein that they can't tell the difference between the models. The Germans would love that, always being up for a "choke" as they tend to pronounce it.

Pricing: Porsche Carrera 4 S from $265,000, Other Carreras from $226,000 to $385,000.

Hot: Traditional styling; simply incredible chassis balance and poise; as quick as but half the price of a Ferrari.

Not: The Cayman and Boxster are even cheaper and no less impressive, though they're not 911s.

Verdict: You can see where every cent spent in 50 years of development has gone into building the 911 C4S.

Well they have a point. While the model has gained and lost weight over the years, grown in size and taken-up water cooling instead of merely allowing the air to do the job, its basic shape is very similar, even if you park a half-century-old model against a brand-new one.

One area of change that has occurred pretty well constantly is the power curve. It has become steeper and steeper to such an extent that normally aspirated models are now quicker than previous turbocharged models, and that curve would have been even steeper had we included the 912 model, a short-lived 1600cc, four-cylinder version of the 911 that started with 90 horsepower (62.2kW) instead of the 2.0-litre, flat-six car's initial 128hp (94kW).

For all that the current 991 series car reviewed here has enjoyed the greatest number of changes in a single model cycle, when compared with the previous 997 version.

Its engines are smaller at 3.4 and 3.8-litres, its wheel footprint is wider and it's 56mm longer over all on a 100mm longer wheelbase. It also has better accommodation, both in terms of volume and quality and thanks to a lot of aluminium being employed in its construction, it's also up to 50 kilograms lighter.

And yes, it all looks pleasantly familiar. Though if you park up next to the old model you'll notice the slimmer rear-light slivers, tidier front lamps too, and a more severely-raked front screen with its base starting a touch further forward than before.

Other changes include electromechanical steering, (lighter and less power-sapping) the option of a seven-speed manual gearbox, though the two-pedal PDK device with a similar number of ratios is quicker and better - but don't take my word for it, test-driver Walther Rohrl said that too.

We all know that the 911's engine shouldn't be out where it is. But 50 years and more than 800,000 buyers can't be wrong, and far from being the skittish beasts the early cars were - and they really were - the newest 911s are pussycats by comparison.

My test car is the Carrera 4 S. The S means it's the hotter of the two engine sizes with 294kW on tap compared with 257kW for the non S, while '4' means it's the all-wheel-drive version. As such, it's the least skittish of all 911s and contrary to most previous cars with a 911 history and that kind of power, it can be as passive and gentle as you want it to be, all day every day.

The all-wheel-drive system allows the Porsche to be, and behave like, a rear-drive car most of the time, because that's what it is. But the set-up can dump all of the engine's power and torque to the front end if its yaw, steering and throttle sensors dictate. But you'd have to be "bloody silly" to achieve that says Porsche.

What you will note is that the Carrera 4 has eliminated even more of that unnerving understeer that earlier 911s used to demonstrate at times. The Carrera 2 had all but shooed it away. However, the all-wheel-drive car makes the 911 feel more neutral in normal driving conditions than any version before it.

But neutral doesn't mean "boring". With such a flexible and, when you need it, astonishingly punchy power unit behind you making one of the industry's most pleasant and emotive engine notes, the transition from one well-poised apex-hugging point in one corner to the turn-in area of the next is quick, communicative and very satisfying. The steering allows very quick inputs when at that turn-in point and such reactions need time to get used to, especially with the almost expected push-out or understeer now out of the equation.

There's lots of grip, but also lots of information coming through the hands and the seat of the pants, and the car feels so much more complete in the twisties than 911s of old. The rear footprint is another 36 millimetres wider than the two-wheel-drive car's and the C4S has extra body muscle to cover it, and very elegantly too.

While cornering, you won't have time to peruse or even spot the information graphic in the right hand dial of the three-instrument binnacle in front of you, but your passenger might want to have a look to know why this car can get around corners so implausibly quickly. The graphic shows the torque deployment front to rear, but frankly it seems a bit gimmicky for a car as serious as this.

As well as that front passenger, you could carry two other others; but they will have to be contortionists, very tiny or party to being surgically inserted into the two tiny perches on offer in the rear. It's better than with pre-991 versions of the 911, but that's faint praise truth be known. I'd call the Porsche a two-plus-briefcase and shopping rather than a genuine two-plus two.

From the front chairs the 991 is a little less snug than before. The dash doesn't dominate, because the wider and longer windscreen allows more light and air into the driving environment. As well, with the new centre-stack design rising to the the dash with the jewellery of alloy-finished switchgear, herringboned on either side, this is a thoughtfully designed and beautifully laid-out driving environment.

The feeling is of good organisation and logic rather than being ostentatious, which is why that all-wheel-drive gauge looked so out of place. The package now includes a launch control should you wish to really impress people, with your arbitrary zero to 100kmh time or standing quarter mile.

Most Carrera owners will use it for track time, as that's really the only place to exercise the 300kmh plus Porsche to anywhere near its potential.

Just for your information, I managed to hit zero to illegal in about 4.32 seconds, which isn't as fast as the car will ultimately go, but I'm probably just a bit to mechanically sympathetic to care.

Some have said that while the C4S is the ultimate iteration of the current 911, if you ignore the track-spec GT-series cars and ignore the upcoming turbocharged version, it has changed the "character" of 911s as we know it.

Well I agree with them, but not in the negative way that they express their reaction to those changes.

The car isn't the unsettled recalcitrant beast it once was when things got messy at road surface level and, my word, the car still handles and corners like a 911 should, only better. And don't worry about the electromechanical steering, it still talks to the driver better than anyone else's does.

It also rides well even on the gorgeous 20-inch rims of the C4S test car.

I crossed previously wince-inducing divots with an implacability I couldn't have imagined in a car so focused and seriously powerful.

Fifty years on since its first flat-six production cars, Porsche has done a great job of refining its product.

You'd expect it to be the best-ever 911, but the fact that even those TV stars who can't tell the difference also call it the best-ever sportscar, full-stop, is a huge compliment.

I don't disagree with them at all. Nice work grandad, that's some axe!